Name

Synopsis

/etc/shorewall/policy

Description

This file defines the high-level policy for connections between zones defined in shorewall-zones(5).

Important

The order of entries in this file is important

This file determines what to do with a new connection request if
we don't get a match from the /etc/shorewall/rules file . For each
source/destination pair, the file is processed in order until a match is
found ("all" will match any source or destination).

Important

Intra-zone policies are pre-defined

For $FW and for all of the zones defined in /etc/shorewall/zones,
the POLICY for connections from the zone to itself is ACCEPT (with no
logging or TCP connection rate limiting) but may be overridden by an
entry in this file. The overriding entry must be explicit (specifying
the zone name in both SOURCE and DEST) or it must use "all+" (Shorewall
4.5.17 or later).

Similarly, if you have IMPLICIT_CONTINUE=Yes in shorewall.conf,
then the implicit policy to/from any sub-zone is CONTINUE. These
implicit CONTINUE policies may also be overridden by an explicit entry
in this file.

The columns in the file are as follows (where the column name is
followed by a different name in parentheses, the different name is used in
the alternate specification syntax).

SOURCE -
zone[,...[+]]|$FW|all|all+

Source zone. Must be the name of a zone defined in shorewall-zones(5),
$FW, "all" or "all+".

Support for "all+" was added in Shorewall 4.5.17. "all" does
not override the implicit intra-zone ACCEPT policy while "all+"
does.

Beginning with Shorewall 5.0.12, multiple zones may be listed
separated by commas. As above, if '+' is specified after two or more
zone names, then the policy overrides the implicit intra-zone ACCEPT
policy if the same zone appears in both
the SOURCE and DEST columns.

DEST -
zone[,...[+]]|$FW|all|all+

Destination zone. Must be the name of a zone defined in shorewall-zones(5),
$FW, "all" or "all+". If the DEST is a bport zone, then the SOURCE
must be "all", "all+", another bport zone associated with the same
bridge, or it must be an ipv4 zone that is associated with only the
same bridge.

Support for "all+" was added in Shorewall 4.5.17. "all" does
not override the implicit intra-zone ACCEPT policy while "all+"
does.

Beginning with Shorewall 5.0.12, multiple zones may be listed
separated by commas. As above, if '+' is specified after two or more
zone names, then the policy overrides the implicit intra-zone ACCEPT
policy if the same zone appears in both
the SOURCE and DEST columns.

If the policy is neither CONTINUE nor NONE then the policy may
be followed by ":" and one of the following:

The word "None" or "none". This causes any default action
defined in shorewall.conf(5) to
be omitted for this policy.

The name of an action. The action will be invoked before
the policy is enforced.

Actions can have parameters specified.

Beginning with Shorewall 4.5.10, the action name can be
followed optionally by a colon and a log level. The level will be
applied to each rule in the action or body that does not already
have a log level.

Possible actions are:

ACCEPT

Accept the connection.

DROP

Ignore the connection request.

REJECT

For TCP, send RST. For all other, send an "unreachable"
ICMP.

QUEUE

Queue the request for a user-space application such as
Snort-inline.

NFQUEUE

Queue the request for a user-space application using the
nfnetlink_queue mechanism. If a
queuenumber1 is not given, queue
zero (0) is assumed. Beginning with Shorewall 4.6.10, a second
queue number (queuenumber2) may be given. This specifies a
range of queues to use. Packets are then balanced across the
given queues. This is useful for multicore systems: start
multiple instances of the userspace program on queues x, x+1,
.. x+n and use "x:x+n". Packets belonging to the same
connection are put into the same nfqueue.

CONTINUE

Pass the connection request past any other rules that it
might also match (where the source or destination zone in
those rules is a superset of the SOURCE or DEST in this
policy). See shorewall-nesting(5)
for additional information.

NONE

Assume that there will never be any packets from this
SOURCE to this DEST. Shorewall will not create any
infrastructure to handle such packets and you may not have any
rules with this SOURCE and DEST in the /etc/shorewall/rules
file. If such a packet is
received, the result is undefined. NONE may not be used if the
SOURCE or DEST columns contain the firewall zone ($FW) or
"all".

LOG LEVEL (loglevel) -
[log-level|ULOG|NFLOG]

Optional - if supplied, each connection handled under the
default POLICY is logged at that level. If not supplied, no log
message is generated. See syslog.conf(5) for a description of log
levels.

If passed, specifies the maximum TCP connection
rate and the size of an acceptable
burst. If not specified, TCP connections are
not limited. If the burst parameter is
omitted, a value of 5 is assumed.

When s: or d: is specified,
the rate applies per source IP address or per destination IP address
respectively. The name may be chosen by
the user and specifies a hash table to be used to count matching
connections. If not give, the name shorewall is assumed. Where more than one
POLICY or rule specifies the same name, the connections counts for
the policies are aggregated and the individual rates apply to the
aggregated count.

Beginning with Shorewall 4.6.5, two
limits may be specified, separated by a comma. In this
case, the first limit (name1,
rate1, burst1) specifies the per-source
IP limit and the second limit specifies the per-destination IP
limit.

Example: client:10/sec:20,:60/sec:100

CONNLIMIT -
limit[:mask]

May be used to limit the number of simultaneous connections
from each individual host to limit
connections. While the limit is only checked on connections to which
this policy could apply, the number of current connections is
calculated over all current connections from the SOURCE host. By
default, the limit is applied to each host individually but can be
made to apply to networks of hosts by specifying a
mask. The mask
specifies the width of a VLSM mask to be applied to the source
address; the number of current connections is then taken over all
hosts in the subnet
source-address/mask.

Example

All connections from the local network to the internet are
allowed

All connections from the internet are ignored but logged at
syslog level KERNEL.INFO.

All other connection requests are rejected and logged at level
KERNEL.INFO.